A subset of Alzheimer's cases may be caused by two copies of a single gene, new research shows

For the first time, researchers have identified a genetic form of late-in-life Alzheimer's disease. Most cases of the mind-robbing disease occur after age 65. A gene called APOE4 has long been considered a key risk factor. But new research says if people inherit two copies of that gene it's not just a risk — it appears to be the underlying cause. About 15% of Alzheimer's patients are thought to carry the gene pair. Scientists say the distinction could have implications for both research and treatment. The findings were published Monday in Nature Medicine.